Efficacy of single-dose pegfilgrastim after chemotherapy for the mobilization of autologous peripheral blood stem cells in patients with malignant lymphoma or multiple myeloma

Background: A single injection of pegfilgrastim has been shown to be equivalent to daily filgrastim in enhancing neutrophil recovery after chemotherapy, whereas the experiences with pegfilgrastim in mobilization of peripheral blood progenitor cells (PBPCs) are limited. Study Design and Methods: Forty unselected patients with lymphoma or multiple myeloma were treated with different chemotherapy regimens followed by 6 mg of pegfilgrastim for mobilization of autologous PBPCs. Patients with an inadequate mobilization (blood CD34+ cells <= 10/mu L after nadir) were given additional daily doses of 10 mu g per kg unconjugated filgrastim. Results: A median blood CD34+ peak concentration of 81 per mu L (range, 10-565/mu L) was found in 30 patients, who had only received pegfilgrastim, compared to 13 per mu L (median, range 4-71/mu L; p < 0.001) in 10 poor mobilizing patients with additional filgrastim. The median yield of CD34+ cells was 9.8 x 10(6) per kg (range, 1.5-88.1) after pegfilgrastim only versus 2.5 x 10(6) (range, 1.7-7.0) in poor mobilizers. Patients who needed additional cytokine administration were those with a more extensive previous antineoplastic treatment and mobilizing regimens containing PBPC toxic agents. Conclusion: The results confirm the efficacy and feasibility of PBPC mobilization with chemotherapy and single-dose pegfilgrastim in patients with lymphoproliferative malignacies. In less heavily pretreated patients, 6 mg of pegfilgrastim after chemotherapy induced an adequate mobilization, whereas dose and schedule in patients after numerous cytotoxic regimens need further investigation.